1995 Johnson/Evinrude Outboards 9.9, 15 four-stroke Service Manual, Page 54Get this manual
Description of Fuel System
1The fuel pump is of the diaphragm-displacement type and is operated by changes in crankcase pressureAlternately, suction and pressure in the crankcase are transmitted to the pump diaphragm
2The carburetor meters and distributes the fuel consumedIt controls engine speed and power output by varying the intake charge densityTo react correctly to wide range of operating conditions, the carburetor has multiple fuel mixing circuits
Mixture enrichment for cold starting is controlled by either choke or fuel primer solenoid
Fuel Pump Servicing
Before replacing suspect fuel pump, remove and clean the fuel filter and install new filter elementAlso, remove the fuel hose from the fuel tank and blow through all passages and hoses with low-pressure compressed air to be sure they are openThis might be the cause of inadequate fuel deliveryIf this procedure does not correct the trouble, test the fuel pump